The goal of this R15 application is to study how exposure to the criminal justice system influences substance use during the transition from adolescence to early adulthood. We adopt a life course perspective and posit that there is no single pattern of substance use and justice system involvement. Rather, it is likely that there are numerous trajectories. A trajectories approach emphasizes that behaviors change over time (i.e. increase, decrease, fluctuate, accelerate, decelerate) and contends that the course of these behaviors is determined by changes in the individual and their social circumstances. We will test three specific aims using 11 years of nationally representative, prospective data from the National Longitudinal Survey of Youth (NLSY97). The NLSY97 is a nationally representative sample of 8,984 males and females who were 12 to 18 years old when they were first interviewed in 1997. Respondents have been interviewed annually since 1997, with data collection ongoing. The data will be analyzed via advanced statistical models - latent class growth analysis (LCGA) and cross-domain analysis of change (CDAC) - using Mplus statistical software. First in Aim #1, we will identify and describe trajectories of justice system involvement, and trajectories of substance use (i.e., alcohol, tobacco, and illicit drugs) from adolescence to early adulthood. We hypothesize that there will be at least three trajectories of justice system involvement, and at least four major trajectories of substance use. Further, we hypothesize that these trajectories will be associated with covariates such as race/ethnicity and gender. Next in Aim #2, we will examine how trajectories of criminal justice involvement influence substance use trajectories from adolescence to early adulthood. Finally in Aim #3, we will examine how educational attainment and employment affect the relationship between criminal justice involvement and substance use. We hypothesize that individuals who were incarcerated for more serious crimes will be less likely to complete secondary or post-secondary school once they are released, and that lower educational attainment will mediate the relationship between criminal justice involvement and substance use trajectories. We also theorize that individuals who were incarcerated will have more difficulty procuring employment once released, and lack of employment will be associated with increased recidivism and substance use. PUBLIC HEALTH RELEVANCE: The study of the relationship of substance use with justice system involvement is of critical concern to public health because (1) the reduction of substance use is an objective of Healthy People 2020; (2) identifying the predictors that increase or decrease youths' initiation of substance use during and/or after their involvement with the justice system, including entering prison, can help inform interventions; and finally (3) racial and economic disparities exist in terms of which youth are exposed to the justice system and how substance use may evolve over time.